Hydraulic drill



Oct 20, 1931. Y B. HUMPHREYS 1,828,604

HYDRAULIC DRILL Filed Sept. 19, 1924 2 Sheets-Sheet l J5 Z' 19 @5w y @a311s 6W J i6 "#9 a] 6 -ff W lIN 4 a ,Mmm 1, l s y wfg-)yn s m. l j; i: ll f C .Z22- will@ l, ,jg 136 n] f F @i dgn dus, I

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HYDRAULIC DRILL Filed sept. 19, 1924` 2 sham-sheet 2Bjiasz-:forinstaneevthe ril-lin p p Hretofore Yirndeepwell-frillihgitthasbeen@ the? practicetefuse:either'cableoperated drills.:y

mns-nummers;ioznmwmifcoow I f1 nnmunxemnmf.

Appiicmanfrmeeiseptember, .1s,1. 1s24.- smul m1138572.

stem is used extendL lf'rmgithe? :bottoms ofif the well, whererthefrworleisbeing1-donet'othef to 1, ofi theawellvcfherexfsuit'a.bl/e1"ineens:areapro@ viedsforfrotetingg-,theestemr.Thesefmethodsffs o-y drilling;present-ga;pr0bl`em;a,s;the; cablesaora A the dri'lllf l.'st lerna:einen become-1:brokenL-which; necessittessthe@pulliiiggofthefdrillifromatheg@ welllvcasingxv-andrlishingf for-fthe'. lo'etapairtv ofcV 'l theidrill; leftin'ithewvell' clueQ-togthei breakage-.3

tion will appear* in nthe following'j description breakageazoccursfth-.thefzresultlfs the :lossJz-olffFi-'anda` acompanying drawingsr2if''considem-adele tim'efzi Twith'f. azf .resultnt trouble: r

andexpenseae,

Onezof thek drill stemsf.

A further1objectfortheinventiomis;to:pre1?, videfa.combinedf:hydraulictspringyoperated,'l drill: of va.,`,construction-i whereby` the entiredrilling,mechanismisilowered;intoatheefrwella'f casingzatotheApoint-1'wherethcmajctuelwork ist Anctheriax'lfdlfrther. object.aotE-``the invenf tion n-f istoiprovidezmcombinedhydraulic. and;springvaoperatedfdrillfr;:deepwelkdrillingipA.stilliurthereobjectfjofthe invention 'is'.tofg provide5f;.ai:combinedr'hyidraulic and v `'springer-- operaterldrill?Anwhich-the -fhydr'aulic lpres'-l A sure rislusedbotlntoi'operate'the`drill andi.A to

washtheg;cuttingsfffrcmrthe well., v

Anothertohje `'vide afhydraulic drill in which the len :eff:.theiinvention .is to' pro-f .constructionif lof. hydraulic l f drill?wherebythe? numbered-operating f parts. are -few,= reducngthezzweightofthedevicel asy aewhole; and; to'l epply-theepower to the" .drill-:.1infsuch-f-aJ manner asy tozreduce to a,v minimum.: the;recoiland?!vibration;of the.,devicef;whi`ch. partlafrotary movementtothe drill.

' 'llh-isy i'nventionereltesfto;improvements/inf, wouldtend-toflift orllstrain, the device inany rauhe drills?"pertainngmore:particularlydreuli "andsprin foperatcdsv i provide a novel lmeans in a'hydraulicdrill otite-partes A Astill further objectofthe invention is to.

for :controlling and directing the hydraulic pressure to'operate therdevice inthe desired.

and, springoperated drill which` isv .simple pit construction andhighlyeicient inoperaonkl l v Another object of the vinvention is to.

thestroke. is variable as desired. Y Other further objects, novelfeatures kof construction and improved resultsy of thev inven'' l.

Imthe drawings: Figurel isa, vert-ical-sectional'view of the beings own:lowered withinfa well casin F1?. y3 isan venlarged* detailv verticalsecfview of the` vulve constructionof the r f.. v

Fig.- 4 lis e:fragmentary enlarged verticaly sectionalview showing themanner in which n lthe lret-aiming ring issupported in the drills` inrxmechanism.l

ig. 5 is `en enlarged vertical sectional view showing they one-wayclutch.y

Fig, -6 is. a transverse*sectionalv view taken onthe line6---6,fliigg,5'.v v

upper ort-ionvofthe drillf,the.-mechansm Fig. V7 is ,a transversesectionalview, similer-*tof Fig..16, showings, modified form of -udrill'head-against theV .tension of a spring and '95! n atea.predetermined time to balance the hy- 'dr'auhcjpressure within themechanism to al- 'low the .drill bit and headto be driven down.-r

wardly by the energy stored in.: the *com-n pressed spring and teyprovide .means to imbroadlly com rising a valve housing A, a cylinderton D a drill a ho low plston rod C carrying a pishead G.

The drilled hole or well is designated by-f the numeral 5 and as iscommon in the drilling of wells a well casing 6 yis lowered into" thehole as the drilling rogresses. This well casinfr extends above t eto ofthe well hole 5 an is provided-wah a @ad 7 with which communicates aninlet pipe or conduit 8 through which is pumped or otherwise suitablyforced by an engine or the like (not shown) the hydraulic pressure fluidused in the operation of the drilling mechanism. The well casing head 7is provided with suitable means 9 which rmits the casing to be loweredas the drilling progresses or to be lifted from the well when desired.The well casini head 7 is further provided with a remova le top or cover10.v

The valve housin A is closed at its top by a head 11 while its ower endis open and adapted for communication with the cylinder B. The cylinderB comprises in reality an elon ated pipe, the upper end of 'which `is'suita ly attached as at 12 to the valve housing while the lower end ofthe cylinder screwthreadedly jor otherwise suitably carries the lowercylinder head E.

The cylinder head E is provided at its lower side with an extendingsleeve 13 terminatin in a head 14 which screw-threadcdly or oterwisesuitably carries the concentrically arranged pipes 15 and 16. The pi e15 is the outer pi e and extends downwar ly a much greater istance thanthe inner ipe its lower end 17 screw-threadedly carrymg a pipe 18 thelower end of which in turn screw-threadedl carries a pipe 19. e

he lower end of the well casing 6 carries a sleeve 20 provided with aninwardly extending circumferential flange 21. The entire drillingmechanism is supported upon this flange through the engagement of thelower end 22 of the pipe 19 with the flange. The hollow piston rod Cextends from within the cylinder B, down through the cylinder head E andits extension sleeve 13 and head 14, throughthe pipes 16, 17 and 18. Thelower end 23 of the hollow piston rod screwthreadedly carries as at 24the drill stem F.

Within the cylinder B the hollow piston rodC is provided with :thepiston D which is adapted vto reciprocate wit 'n the cylinder.

a cylinder head E, a drill stem F As clearly appears the piston rod hasan ex'- tending end 25 above the piston and this extending end isprovided with ports or openings `26 which are in communicationv with thecylinder B while the lower end 23 of the hollow piston rod is incommunication with the channel 27 extending the vvlength of the drill.stem F. `The channel-27. extends downwardly through the drill head' Gterminating vin outlet openings 28.

Againreferring to the pipe 16 which is the inner of the twoconcentrically arran ed pipes, itwill be seen that the lower end of t ispipe screw-threadedly carries as at 29 a sleeve 30 provided at its lowerend with an inwardly extending circumferential ilange or shoulder 31'.Carried between the flange 31 and the lower end 32 of the pipe 16 is a slinted or spirally threaded nut 33. It will e seen that that portion ofthe hollow piston rod C which passes through this` splinted nut isprovided exteriorlywith spiral threads 34v or the like. e

This splinted nut is provided for the purpose-of rotating the hollow`piston rod and the drill stem-andhead. y It will be readily seen thatthe nut is locked against vertical movement. The nut 33 is furthermoreprovided with some common form of clutch such as appears in Figs. 5 to 7inclusive construction whereby it is locked against rotation on the uward movement of the hollow piston rod 't ereby lcausing the rod torotate. The clutch arrangementof the'nut is such however 'as to allow itto rotate on the downward movement of the iston rod land consequentlytheA piston rod, ill v,stem and hea'dar'e'not rotated through 'theirdownward movement.

Surrounding the piston rod C between the splinted nut 33 and theenlarged portion 35 adjacent the end of the piston rod isa spiral spring36. The u per end of'this spring en-l gages the lower si eof the collaror sleeve 30 while the lower end of the spring engages the enlargedportion 35'of the drill stem. It will be seen that any upward movementof the piston rod will cause thisspiralor coiled spring the membersmentioned a space or channel-37. yAdditionallyit will ber seen that thewell cas-vI atv ion

ing does notfit tightly. the well or` drilled hole 5. e y W Within thevalve housing A lis a sleeve valve 3,8`prov1ded at its lower end with anen- `largedjhead 39 :adapted to seat upon the taofthe-.cylinder B. i li-I ringmediately above the ``valve seat 40 the cylinder isfprovidedwithports'41 which pered valve seat 40 carriedby the. upper end masserare in vcommunication with the interior ofthe well casing 6 and arehkewise in communication with the interior Aof the valve-housingA whenthe vvalve 38v and its enlarged head 39 is cient s1ze to accommodate thewell casing and lifted.4 TheA upward movement of the valve is limited bythe shoulder 42 of the valve head coming into engagement with the lowerend of the valve housing while the downward movement of the-valve is ofcourse limited by thevalveseat40.v

Suitably fastened within the extendingend 25 of the hollow piston rodGand closing it is a valve rod 43 which'4 extends through the sleeve 44of the valve head 39, terminating within the valve housing in anenlarged head 45. Surroundin the valve rod 43 between the u per end othe .valve head sleeve andthe en arged head 45 of the rod is a coilspring'4.

A second coil spring 47 surrounds the valve stem 43 withln the cylinder`B. This spring rests upon the upper end of the hollow piston rod and theupper end of the s ring is adapted for engagement with `the s eeve 44 ofthe enlarged valve head 39.

The cylinder B is rovided at its lower end with a port 48 w ich is incommunication with the well casing channel 37.

The drill stem F is provided with an enlarged head 49 at its upper end.This head however is of a size which would permit its assage through thesleeve 20 carried by thellower end of the well casing. From this it willbe seen that in the event the drill stem became broken it would bepossible to lose the drill in the well hole. To guard against this thereis provided a split ring 50 which rests upon the shoulder 51 adjacentthe upper end of the pipe 19. In the event that the threaded connection2 4- of the drill stem with the lower end of the piston rod becomesdis-connected or broken it will be seen that the split ring 50 willengage the head 49 of the drill stem and prevent the stem from droppingfrom the pipe 19 or the well casing.

To permit the drilling of a hole of sufliat the same time provide aconstruction of drill head which will allow the head to be drawnupwardly through the well casing the head is provided with under-reamersl 52. These under-reamers are of a common f construction, beingpivotally mounted at 53 and normally held in their expandedpositions dueto a spring 54. As the drilling .-H mechanism is pulled' from thewellcasing f these under-reamers will spring inwardly against the tension ofthe coil s ring 54 and 6ov thereby permit the passage of t e drill headthrough the well casing.

A wei ht 55 is suita ly mounted upon the i to of t e valve housing A.This weight ho ds the entire drilling mechanism in place upon theshoulder 21 of the sleeve 20 at the lower end of the well casing. Thisweight 'i dr1ll head.

Suitably fastened within the wei ht 55 is a cable 56 which passesupwardly t rough a stuing box 57 or some like littin to a pointabove'the well. It will be readi y apparent that upon removing the cover10 of the casing head 7 that the entire drilling mechanism whichincludes the valve housing A the cl linder B, the ipes 16 17, 18 and 19and Athe rill bit F, and) head (il can .be removed from the well casing.This arrangement is very important as it permits the ready and rapidremoval of the drilling mechanism from the well to effect any repalrs oradjustments and likewise ermits the rapid installation of the drillingmechanism as it is only necessary to lower the mechanism until the lowerend of the pipe 19 rests upon the flange 21 at the bottom of the wellcaslng.

It will also be seen that due to the manner in which the drillingmechanism can be lowered into the well 'casing and removed from thecasing that the entire mechanism can be assembled on the ound above thewell. This of course woul be necessary because the split ring 50 wouldvhave to beplaced in position before the pipe 19 is screwfi into placeupon the lower end of the p1 t is not thought necessary to go further inthe assembling of the drill as this can be readily accomplished byanyoneskilled in the art as the drill is not at all complicated, it beingmerely necessary to position the proper parts by screwing them intoplace in their proper positions as shownl in the drawings. l

Operation The fluid which will preferably be used as the motive powerfor the drill will be water as is common in rotary drilling.

This fluid will be forced under high pressure, by some suitable engineor the like, into the inlet 8 in the head of the well casing.

With the parts as shown in the figures of the drawings the piston D isabout to start its upward stroke.

The highpressure Huid passing down the well casing in the space 37enters the port 48 at the lower end of the cylinder B and causes anupward'pressure upon the piston. As the piston ascends it carries withit- 'the hollow piston rod, and the drill bit and drill head, all ofwhi'ch are in operative'engagement. It will be seen that as the/pistonrises it also carries with it the valve rod 43 which is fesin as it addsto the impact stroke of the v the channel 27 in t tened in the upperopen end of the piston ro The fluid in the cylinder B above the pis--tonv is discharged through the piston rod orts 26 as the piston ascendsand passes downwardly throu h the hollow piston rod, e drill bit andoutwardl through the channel 28 in the drill head, fbrcing the cuttingsupwardly out of the .well on the outside of the well casing.

It will be also seen that due to the upward movement of the piston andpiston rod that eventually the coil sprin 47 surrounding the valve stemwill engage t e ortion 44 o the enlarged valve head 39 an force thesleeve valve 38 from its seat. This valve is so made that very littlepressure is required to raise it from its seat. It will be understoodthatv hi h pressure fluid is constantly on the outsigo `of the valvehead and the valv(` is therefore held on its seat until raised bytheaction of the u ardly moving piston rod and the spring 4%. It will alsobe understood that as the piston ascends the coil s ring 36 is comressed between the enlarge piston rod lportion and the sleeve 30 whichholds -the splinted nut 33 in place. t

When the piston has reached the top of its stroke the sleeve valve hasbeen lifted from its seat and high pressure is allowed to enter theports 41 and flow downwardly beneath the valve head into the cylinder Babove the pise ton. This high pressure likewise enters the Hrl valvehousing A through the open end 59 of r the sleeve valve.

It will now be seenthat high 'pressure is acting on both the u persideof the piston A and on the lower si e of the piston, as the ports`48are always open, and is balanced.

As the drilling mechanism has ascended th drill stem and head have beenrotated due to the 4splinted nut 33 and the spiral teeth 34 on theexterior of the hollow piston rod.-

The piston, piston rodz drill stem and drill head will now start thelrdownward stroke the driving power being spring 36l As the pistondescends the piston rod, drill stem'anddrill head are carried downwardlybut are not rotated because the clutch of the splinted nut operates torelease and allow the slinted nut to rotate as the piston rod passes trough it. r

As the piston continues to descend the fluid the compressed coil in thecylinder belowr the piston is forced out'- wardly throughthe ports 48 upthe well casing.

It will also be seen that as the piston descends that eventually theenlarged head of the valve rod will engage and compress the coil spring46 which will, after being suiii- -ciently compressed overcome thepressure on the valve head 39 and cause the valve to seat and thus cutol the high pressure iuid being 5 delivered into the .cylinder above thepiston.

` The downward movement'of the piston andr drill is rapid so-thattheydrill w1ll strikeY the bottom of the well' or hole'forciblysstrikin'gor -dilerent'-positaonon` each stroke due to the fact'that'the drillheadA in a different place is rotated during its upward movement.- Y

and downward 'strokev of thedrilla-n'dcoi-actY ing 'partshas beendescribed;r 'Ihetupward stroke of the drillis now ready to begin iagainand is merely la repetition-ofthestroke.here-- tofore described. 1

It will ofcourse be-understoodthatfasthe ,drillingproresse's the wellcasing is lowered.A

lioweverthe 'lowerfend of the well' f At all tlmes casingris' above the`bottom 'offthe well or' hole 'bein drilledrl It has been heretoforelength of thestroke of the dri-llis'fvariable.

This is accomplished through vthe medium of the well casing as it willbe clearlyf'seen that the length of' the downward stroke. of the drillis controlled entirely bythe distancethe lower end of the well casinl'is above the'bottom. of the hole being dri led; -Toshorten the strokeof the drill it is only necessary to lower the well' casing until itslowerfend is quite near the bottom of the holei l The action of thevalve to'changezthe direction of movement of the piston. is automaticand will act immediatelyupon theim- Ract of the drill head with thebottom of the ole irres ective ofthe lengthvo the'down'- ward stro eofthe drill.- Q i j With the valvepin la closed position the Huid underpressure-from the lpressure pro viding mechanism' above orlad'j acentthewell of the valve is acting on a greater areal and exerting a downwardforce thereuponthan the area subjected to the upward pressure and,furthermore the pressure or'headfof the fluid acting to li tthe valvefis less thanthe pressure or head of the fluid exerting an upwardpressure u onthevalv'e, forth'e reason that what little uid is present'above thel iston at the time the piston starts u'pwar is beingdischarged through 'the hollow drill bit or stem as the pistonisraised.v

When the'spring 47 presses'up'ovn tli'vglye 1 guide fins Asuiici'entlyto overconiefthe unbalanced pressure on the Vvalvevvliicliiisholding thevalve-closed,`the valve willv openarid the high pressure iiuid' enteringthef ports 41 will pass under the valve and into the cylinder above thepiston. The extensinfbelow: the "l" .mentioned thatV the n'lfm Acomplete reciprocation of afull upward cylinder.

' nism will be pulled from the Losanna valve carrying the fins partlyfills or obstructs the opening through the valve seat and, hence, formsaA restriction. through which the hi h pressure fluid must pass to getinto e When the valve is opened,cthe downward movement of the 'drill andpiston is very rapid, due to the ener stored in the driving spring 36and thus t e area of the cylinder ,above the piston into which the fluidis liowing is rapidly increasing. Furthermore the passage of the fluidthrough the restriction causes a material acceleration of the speed offlow of said Huid and causes what might be termed an ejector action inrespect to the passageways 59 in the valve thus preventing a building upof pressure in the valve housing above the valve in an amount equal tothe pressure head existent under and acting up- .wardv upon the valvehead 39. Due to this differential of pressure the vvalve remains in itsopen ostion until the downward movement of t e piston is arrested.l

When the piston for any reason stops its downward movement the flow offluid beheath the valve and throu h the restriction is reduced, infact,racticay stopped so that the pressure hea in the restriction, in thechambers below the valve and above the valve are practically the same asexist adjacent the ports 41 and above the restriction. The pressure headacting upwardly and downwardly upon; the valve are practically balancedand the spring 46 acts and closes the valve and the entire operationbegins over again.

From the foregoing 1t will be seen that the a paratus isautomaticinsofar as reversin t e direction of movement is concerned an that itswork will be continuous as long as 4 hgh pressure fluid' is supplied tothe well casing inlet 8.

It is proposed that in practice that the well casing which is useddurlng the drilling operation will be left in the well after it has beencompleted. The entire drilling mechacasing for use lupon another '0b. f

It will be a ditionally seen from the foregoing description that acombined hydraulic and s ring operated drilllng mechanism is provi edwhich can be readll and quickly lowered into the hole being rilled, orremoved from the hole, and that as the drilling takes lace, the cuttingsare washed upwardly ancyoutwardl from the hole.

Having thus dyescribed my invention what I claim and desire to secure byLetters Patent is 1. A drilling machine, comprising a drill, areciprocatinglpiston for imparting movement to said dr' means forsupplying liquid pressure and said liquid pressure acting on saidpiston, means to alternately direct a portion of, said pressure abovesaid piston, 5 and resilient means compressed by said piston and thedrill for direction,

2. In a drilling machine, an inner and an outer pipe, a reciprocatingmember within the inner plpe carrying a drill, means for supplyingliquid pressure and said pressure communicating with one of said (pipesabove said reciprocating member, an reciprocating means above saidreciprocating member for alternately directing a portion of the'pressure above said reciprocating member to balance the pressure aboveand below the same.

3. In a drill, the combination with a cylinder carrying a piston adaptedto be reclprocated and thereby impart movement to the drill, means forsupplying liquid pressure to said cylinder, means to alternately directa portion of said pressure above said piston,

driving said members in one and resilient means for driving said pistonA and drill in one direction arranged to be compressed b the upwardmovement of the pis-l ton and ill.

4. In a drill, means for supplying liquid prewure to said adapted forreciprocation in said cylinder and provided with a piston rod carryingal drill, said pressure acting constantly on said liston to lift thesame, means to alternately 'rect a portion of said pressure above thesaid piston, and resilient means compressed by the upward movement ofsaid piston and adapted to drive said piston downwardly at apredetermined time.

5. A drill, means for supplying liquid pressure to sai'd drill,comprising a cylinder, a piston adapted for reclprocation in said cyinder, a hollow piston rodfor said cylinder carrying a drill, saidpressure acting constantly on said piston to lift the same, meansoperated by the movement of said piston for alternately directing aportion of said pressure to act upon the opposite side ofsaid piston,resilient means compressed by the upward movement of said piston, andsaid hol low piston rod in communication with the cylinder above saidpiston, whereby the high pressure is discharged throu h the said pistonrod on the upward stroke o vthe piston. n

y 6. In a pressure drill, a reciprocating piston in operative engagementwith the drill, pressure means providing pressure acting constantly tolift said piston, means separate drill, a cylinder, a piston c anddistinct from sald piston to divert a ortion of said pressure above thepiston to alance the pressure upon the same, andi meals to drive thepiston and drill downwar 7. In a drilling mechanism, a reci rocat- 8. Ina drilling mechanism, a reciprocating piston in operative engagementwith the drill, a cylinder for said piston, fluid pressure providingmeans, fluid pressure acting constantly on said piston to raise it,means to balance the pressure above and below said piston, means todrive said piston and drill downward, and means operating said fluidpressure balancing means at the time of the drill impact to direct theentire fluid pressure upon the lower side of the piston to lift thedrill.

' 9. In a fluid pressure loperated drilling mechanism, a cylinder havinga piston adapted for reciprocation therein, a hollow piston rodconnecting ,the iston and the drill, means for providing uid pressure tothe cylinder to lift the drill, separate means for driving said `drilldownward, and communication between the cylinder and the hollow pistonrod, whereby on the up stroke of the p'iston the fluid in the cylinderis discharged through the hollowpiston rod and washes out the cuttingsofthe drill.

10. In a drilling mechanism, a drill and drill stem having internalpassage-ways with outlets adjacent the drill end, a piston having ahollow rod having connection and communication with the drill stempassage-Ways,

fluid pressure providing means for providing pressure to opposite sidesof said piston for actuating the drill, a cylinder for said piston,.andthe hollow piston rod in communication with the cylinder above thepiston, whereby the fluid above the piston is forced down the piston rodand outwardly through the drill on the upward movement of the piston.

11. In a pressure drill, a reciprocating piston in operative engagementwith the drill, pressure means providing pressure acting constantly tolift said piston, a valve separateand distinct from said iston to diverta portion of said pressure a ove the piston to balance the pressure uponthe same, and means to drive the piston and drill downwa-rd` 12. In apressure drill, a reciprocating piston in operative engagement `with thedrill, pressure means providing pressurel acting constantly to move thepiston in one direction, a valve to divert a portion of said pressure tobalance the pressure upon the pist0n,.separate means to drive the pistonin the opposite direction; and a spring moving said valve to a closedposition immediately v upon the impact of the drill.

13. In a pressure drill, a reciprocating piston in operative engagementwith the drill, pressure means providing pressure. acting constantly tomove the piston in one direction, a' valve to divert a portion of saidpressure to balance the pressure upon the piston, said valve normallyclosed, means actuated by the piston to open said valve when the pistonis at one end of its stroke, separate means for driving the piston inthe opposite direction, and means closing said valve immediately uponthe impact of the drill.

14. In a pressure drill, a reciprocating piston in operative engagementwith the drill, pressure means providing pressure acting constantly tolift said piston, a valve operated by the upward movement of the saidpiston for diverting a portion of said pressure above the piston tobalance the pressure upon the same when it has reached the end of itsupward stroke, means to drive the piston and drill downward, and a sring for closing said valve and the inlet o pressure above the pistonimmediately upon the impact of the drill.

1`5. In a pressure drill, a reciprocating piston in operative engagementwith the drill, pressure means constantly providing pressure at one sideof the piston to move the same in one direction, a valve operated by themovement of said piston to direct a portion of the pressure to theopposite side of the piston to balance the pressure at the oppositesides thereof, and resilient means to move said piston and 'drill whensaid pressure is `balanced on the opposite sides of said piston.

16. In a drilling machine, a pair of concentrically arranged pipes, areciprocating piston movable in the lnner pipe and having operativeengagement with a. drill, a valve at the upper end of said inner pipeand normally closing said ipe end, means for providing and deliveringfluid under pressure to the outer pipe, constant communication betweensaid inner ipe and said outer ipe below said piston ibr the admission ofuid under pressure, said piston movable u ward by said fluid pressure,said piston a apted upon its upward movement to engage and open saidvalve and permit the admission of fluid under pressure above saidpiston, resilient means to move said piston and drill downwardly` whensaid valve is open, and said valve automatically closing upon the impactof the drill and the stoppage of downward movement of the drill andiston.

17. In a pressure drill, means or supplyl,.:u'

ing liquid pressure to said drill, an inner and an outer pipe, adrilling mechanism within the outer pipe, a reciprocatin member Withinthe inner pipe carrying a ill, said pressure communicating with one ofsaid pipes V abovev said reciprocating `member, a valve movable by themovement of said reciprocating member for directing the pressure tobalance the same at either side of said reciprocating member, andresilient means for driv- 125 ing said reciprocating member Vwhen saidpressure is balanced as described.

18. In a pressure drill, a reciprocating piston in operative engagementwith the drill,

pressure means providing pressure acting constantly to lift p ated bythe upward movement `ofksaid"`pis ton diverting a portion ofsaidjpressure 'f above thepiston tobalance the pressure u on saidpiston,y means operthe same when it has reached the end o its upwardstroke, means to drive the pistony and drill downward, and means foractuating said-` pressurer diverting/ means to prevent the` inlet ofpressure fluid above 'the piston immediately u on the impact of thedrill.

In testimony w ereof I hereunto aix my signature.

IRA B. HUMPHREY S.

y nu

